Pivotal connection



July 21, 1942. .H. DODGE PIVOTAL CONNECTION Filed May 9, 1939 lNVENTORHOWARD M. DODGE BY D ATTORNE s Patented July 21, 1942 FFICE PIVOTALCONNECTION Howard M. Dodge, Wabash, ma, asslgnor to The General Tire aRubber Company, Akron, Ohio, a corporation of Ohio Application in, 9,1939, Serial No. 212,024

1': Claims. (c ear-as) This invention relates to pivotal and resilientconnections and more particularly to such connections between memberswhich are separated or insulated from one another by resilient rubbercushions or bushings.

In suspending the frame of an automobile or.

other vehicle on the running gear it is customary to employsemi-elliptic or similar leaf springs, which are connected to chassis orframe by means f shackles. It has been proposed to bush the shackleconnections between the springs and the chassis by means of rubbercushions which are effective in minimizing noise. and vibration.

and also in reducing the wear and making it untion, so that in a generalsense it may be said that the operating characteristics of the vehicleare improved. The forms of rubber bushings and cushions used have beenvaried to suit the particular requirements of themanufacturer.

A principal object of the invention is to provide an improved pivotalconnection and rubber bushing therefor which is adapted for use in awide variety of coupling connections, and which has improved operatingcharacteristics. More specifically, the invention aims to provide abushing of this. character in which the inner end of the bushing issubjected to circumferential tension while, if desired, the outer end ofthe bushing may be subjected to. axial compression.

Another object of the invention is to provide a pivotal connectionhaving a rubber bushing which minimizes the wear between the parts andis of increased efiectiveness in damping out detailed description ofsuitable embodiments of the invention made inconnection with theaceompanying drawing, in which: I

Figure 1 is a fragmentary detail partly in section and with parts brokenaway showingthe connection a a shackle to one end of a leaf spring andemploying my improved rubber cushions or bushings; 1

Fig. 2 is a sectional detail taken substantially on the line 2-2 of Fig.l;

Fig. 3 is a detail partly in section showing one oi my improved bushingsin its normal shape;

Fig. 4 is a view partly in section and with parts removed showing thestructure of Fig. l in the process of assembly; 1

Fig; 5 is a fragmentary sectional view showing a modified form orpivotal connection embodying the present invention;

Fig. 6 is a view partly in section showing a modified type of bushing orcushion embodying, the invention in its natural shape;

Fig. 7 is a fragmentary sectional view showing another pivotalconnection embodying the connection; and

Fig. 8 is a viewpartly in section showing the bushing or cushionemployed in the construction of Fig. 7 in its natural shape.

Referring to the drawing by numerals of reference, which indicate likeparts throughout the several views, the invention will be firstdescribed in connection with the embodiment thereof illustrated in Figs.1 through 4 wherein a spring eye A receives therethrough a pintleassembly B, and rubber cushions or bushings C and D embrace the pintleassembly to separate the same from the eye A. The spring eye A may be ofconventional shape and the aperture therethrough which receives thepintle assembly is preferably cylindrical and of greater axial length 1than diameter. Each of the bushings C and D is formed of a suitableresilient rubber composition having approximately the stifiness orconsistency commonly employed in the tread portions of pneumatic'vehicletires. The bushings may be formed by any conventional process, such forexample as molding, and in their normal vulcanized form (Fig. 3) have abody portion I which is substantially frusto-conical in shape. An axialpassage or aperture is formed through the center of the bushing and aportion 2 thereof within the body I has walls which are of substantiallyfrustoconical shape. At the inner or small diameter end of the bushing,which end is normally disposed interiorly of the spring eye A, is formeda radially inwardly 'or centrally extending flange 3 which is preferablycircum inner end portion of the passage through the bushing.

At'the outer orlarge diameter end of the bushing is formed a radiallyextending, outwardly directed flange 5 which is preferably cir- Thepintle assembly B extends between spaced connecting members I and IIwhich may comprise Part of a conventional shackle construction.

If desired, part of the pintle assembly, including end members 9, may beintegral with the connecting members l0 and II, as shown, The endmembers have substantially fiat circular faces 12,

which axially compress the rubber cushions as will later appear. Theconnecting members I'll and II, or one of them, although stated to beportions of a spring shackle construction or spring bracket assemblywell known in the art, may, if desired, be members of other types ofpivotal connections. The invention is contemplated for use in aconstruction wherein a pivotal or oscillating type of movement oflimited amplitude occurs between the pintle assembly B and the springeye A.

Each of the circular faces i2 is of a diameter or dimensionsubstantially equal to the outside diameter or dimension of the springeye A, and the faces are directed toward one another and disposed inspaced parallel relation across the opposite ends of the spring eye.Extending from the central portions of the surfaces [2 are cylindricalthimbles II which are of less diameter than inside wall or surface l5 ofthe spring eye and are axially aligned with one another and extend intothe spring eye from opposite ends thereof. These thimbles have recessedends IE to provide axially directed circular flanges l3, and thethimbles are eye, and before the pintle assembly is drawn together,inner or small diameter ends 24 of the bushings are separated from oneanother.

The large diameter end of the bushing passage, defined by the wallportion 6, is of suflicient cross sectional area to accommodate the endof one of the thimbles it without material distension of the bushing,Upon drawing the ends 3 of the connecting members and II together,

such for example as by'means of the bolt ll, thethimbles ll engage thefrustoconical walls 2 of the passages through the bushings to distendthe body portions thereof. In Fig. 3 the full lines indicate a bushingin its normal and unstressed shape, while the broken lines show theapproximate shape of the bushing when stressed and in place in thepivotal connection. This distension places the innerend portions of therubber bushing bodies under circumferential tension, and also axiallyalongates the bushings, 'so that their inner ends 24 abut one another asshown in Fig. 1. During the assembly, the recessed ends it of thethimbles have circumferential seating engagement with inner walls 25 ofthe inner flanges 3 to assist in the axial elongation of the bushings,and

the circular, axially directed flanges or rib members l3 bite into anddeform the inner ends of of such length thattheir inner ends are spacedfrom one another within the eye. As shown in Fig. l, the thimbles [4 maybe integral with the respective end members 9 of the connecting members[0 and l l, and the parts may be secured.

together by an axially disposed pintle bolt I1 which extends through anaxial hole IS in the end 9 and the thimble H of the member iii. Thethreaded end of the bolt I1 is threadedly engaged in an axial socket [9formed in the thimble M on the connecting member II, and head 20 of thebolt seats against the outside of the end member 9 of the connectingmember i0 so as to draw the ends 9 of the members 10 and II toward oneanother when tightened.

In assembling the pivotal connection the bushings C and D are placedwith their inner or small diameter ends within the opposite ends of thespring eye A (see Fig. 4). In this position sides 2| of the outerflanges 5 of the bushings have circumferential seating engagementagainst op-. posite end walls 22 of the spring eye. The outer wall ofthe body I of each of the bushings is spaced from the inner wall l5 ofthe spring eye A throughout the major part of the length of the bushingbody, as indicated at 23, Fig, 4. Each of the bushings C. and D isshorter, axially, in

its normal or unstressed shape than when in final position, so that, asshown in Fig. 4, when a pair of bushings is initially placed within thespring the bushings to lock the bushings in proper position. Thethimblesmay also effect some axial compression of the inner flanges 3 during thefinal stages of tightening the assembly. Also, during the finaltightening of the connection assembly the outer flanges 5 are axiallycompressed between end faces 22 of the spring eye and the circular facesI'2 of the ends 9 of the connecting members l0 and ii. It is to benoted, however, that the outer flanges 5 of the bushings aresubstantially without circumferential elongation and that thecircumferential distension of the bushingsoccurs almost wholly at theinner ends thereof. .One effect of circumferential elongation of thewalls of the frustoconical portions of the bushings, particularlyadjacent the small diameter inner endsthereof where the greatestelongation occurs, is to reduce the thickness of such walls.Accordingly, the wall of each bushing, whenin assembled or stressedcondition, is of substantially uniform thickness from end to end.The-degree of taper, or progressive increase in thickness of the wallsof the body portion of the bushing from the flange 5 to the flange 3 iscalculated, when designing the same, so that upon distension of the sidewalls by the insertion within the bushing of a substantialy cylindricalthimble,

with the attendant axial elongation which occurs,

the wall thickness becomes substantially uniform and the externalsurface of the bushing becomes substantially cylindrical.

Fig. 5 shows a modified construction in which the connecting members l0and II of the previous figures have been replaced by spaced, parallelside plates 21 and 2B, which may be the regular side plates of anordinary shackle construction, and have ends which present oppositelydisposed flat faces 29 for circumferential seating engagement withopposite'ends 30 of the,

bushings C and D. The ends of the side plates 21 and 28 are held anddrawn together by a pintle bolt 3| which extends axially through thecenter apart relation on opposite ends of the bolt 3| other.

D-in the pivotal connection assembly. One ad- 1 vantage of theembodiment of the invention shown in Fig. 5 is that the assembly may bedisconnected without withdrawing the thimbles 33 or bushings C and D.

While in the previously described {embodiments of the inventioneachpivotal connection employed a pair of substantially identical cushionsor bushings C and D which are cooperatively used and abut one another atthe center of the device, it is also contemplated to form single piecebushings which may replace the pair of bushings C and D. Such a singlepiece bushing is shown in Fig. 6 and comprises a resilient rubber bodyhaving frusto-conical portions 35 and 33 each of which approximatelycorresponds in shape to the body portions i of the single bushings orcushions previously described.

The walls of the portions 35 and 36 of the bushing body progressivelyincrease in thickness toward center 31 so that central wall portions 33are materially thicker than end wall portions '39. Furthermore, when thebushing is in its normal or unstressed, the central part 31 of the bodyis of less diameter than the ends thereof. A radially outwardly directedflange 40 is formed on each'end of the bodyand is circumferential inextent or substantially so. These flanges correspond to the outer endflanges 5 previously described.

A passage extends axially through the center of the bushing to receivethe pintle, having at each end thereof a relatively short cylindricalportion 4! which lies radially inwardly of one of the end flanges 40.The pintle. aperture also in- .cludes portions having frustoconicalwalls 42 within the portions 35 and 36 of the body. At the center 31 ofthe body an inwardly extending flange 43 is formed and has an inwardlydirected "cylindrical wall 44 which defines the central portion of thepintle passage through the bushing. The flange 43 in this embodiment ofthe' invention performs the function of the flanges 3 of the bushings Cand D previously described.

In assembling a so-called double bushing of the character shown inFigure 6 in a pivotal connection the. bushing isaxially elongated bystretching the .body portions 35 and 36, particularly adjacent thecenter 31, and the bushing is also circumferentially distended adjacentthe center so that while the annular flanges 40 are subjected only toaxial compression by members of the pivotal connection which maycorrespond to the ends 3 of the connecting members In and II, or faces23 of the side plates 21 and 23, the central part of the double bushingis circumferentially distended and may also be axially elongated. Thebroken lines of Fig. 6 illustrate one form which the bushing,illustrated in its normal position by the solid lines, may take whenassembled in a pivotal connection.

Figs. 7 and 8 illustrate an embodiment of the invention which may beused for various pivotal connections, such for example as in thesteering mechanism of an automotive vehicle. A cylindrical metal sleeve46 is provided with an annular inturned radially directed flange 41 atone end and an annular radially directed out-turned flange 43 at the.oppositeend, the two flanges preferably being substantially parallel toone an- This sleeve is adapted to be circumferentially embraced by asuitable split band or ring, not shown, so that upon tightening of theband or ring the sleeve is flrmly held thereby. A connecting member 43,which is to have limited pivotal movement relative to the split ring orband, has a spindle which extends axially through the sleeve 46, beingseparated from the latter by a tubular rubber bushing shown in itsnormal shape 'or form in Fig. 8. This bushing has a frustoconical bodyportion 53, which corresponds to the body portion I of the bushing shownin Fig. 3. and at-its outer or large diameter end the bushing has anoutwardly directed radial flange 5| which corresponds tothe flange 5previously described.

Adjacent the small diameter end of the bushing is a circumferentialgroove 52 which receives the inwardly directed flange 41 of the sleeve46 when the connection is assembled. The passage which receives thespindle of the connecting member 43 includes a relatively shortcylindrical portion 53 defined by the inner circular wall of the flange5| and which is of approximately the same diameter aslarge portion 54 ofthe spindle.

The central portion of the axial passage through the bushing is definedby inner wall 55 of the body portion of the bushing, which wall issubstantially frustoconical in shape. At the small diameter end of thebushing is a passage or aperture portion having a substantiallycylindrical wall which is the inner side of a circular inwardlydirected, radial flange 51 corresponding to the flange 3 previouslydescribed. The formation of the annular groove 52, in eflect, provides aradially outwardly directed circular flange 53 on the small diameter endof the bushing.

In assembling the connection shown in Fig. '7, the bushing is placedwithin the socketlike sleeve 45, the outer wall of the body portion 53of the bushing being initially spaced from inwardly facing cylindricalwall 53 of the sleeve similarly I to the manner in which the bushing Cis separated from the inner surface of the eye A, as previouslydescribed and illustrated in Fig. 4. The'small diameter and of thebushing is then worked through opening 6i,'deflned by the flange 41, sothat the latter may seat in the groove 52. The spindle of the connectingmember 43 is then inserted through the passage or aperture in thebushing so that small diameter end portion 62 of the spindle passesthrough the portion of the bushing aperture at the small diameter end ofthe bushing. During this movement the large diameter portion .54 of thespindle acts similarly to the thimbles I4 and .33, previously described,to circumferentially distend and axially elongate the small diameter-endand thick sectioned portion of the bushing.

A metal washer 63 is received on the outer end of the small diameterportion 32 of the spindle A circular flange 65, on the connecting member49 at one end of the spindle portion 54, is

formed with a circular flat surface 63 which engages end 31 of thebushing to compress the V outwardly directed flange 5| thereof againstthe flange 43 of the sleeve 46. Accordingly, both flanges on the smalldiameter end of the bushing and also the flange on the large diameterend of the rubber bushing are subjected to axial compression in theassembled pivotal connection. While the flange 5| is substantiallywithout circumferential distension or elongation, the flange 51 and alsothe body portion 50 of the bushing are circumferentially elongated.

In each of the embodiments of the invention .shown in the drawing anddescribed above the resilient rubber bushings are arranged to beconfined between substantially concentric surfaces of members which areadapted to have limited pivotal or oscillatory movement relative to oneanother. The inner and outer surfaces of the bushings are held infrictional engagement with the relatively smooth and cylindricalsurfaces of the pintle and socket, respectively. At the inner end orportion of each bushing the rubber is circumferentially tensioned aroundthe pintle, so

as to tightly embrace the same. A construction of this character is ofincreased effectiveness in resisting torsional stress applied to theconnection. At the same time, the end' flanges are maintained underaxial compression, so that the connection is capable of withstandingaxial thrusts of one member relative to the other. Although thefrictional engagement between the surfaces of the bushings and thesurfaces of the pintle assembly and socket resists torsional stress ortwisting of one part of the connection relative to another, it is animportant feature of the invention that if an exceptional torsionalstrain be applied, the rubber bushing may slip or slide relative to thepintle or'socket, or both. In this fashion, injury to the pivotalconnection or the parts thereof is avoided. Because of the difference indiameter of the pintle and socket, slippage would normally occur betweenthe bushing and the pintle, if the pressure between the bushing and bothparts of the connection engaged therewith were equal, or a greaterpressure prevailed between the bushing and the socket.

If the bushing were forced over the pintle to distend the bushing, andthereby increase the pressure between the pintle and the bushing,slippage might then occur only between the bushing and the walls of thesocket. In accordance with the present invention, however, one end orportion of the bushing is forced over the pintle,

or a portion thereof, to distend such portion of the bushing andcircumferentially tension the same to promote a tight gripping of thespindle, which the other end or another portion of the bushing is forcedor pressed tightly against the walls or end portions of 'the socket.Hence, should such a torsional strain be imposed on the connection ascannot be wholly absorbed by radial distortion or twisting of thebushing, then slippage between the bushingand pintle occurs at one endor portion of the bushing while another end or portion of the bushingremains in nonslipping relation to the pintle. Similarly, one end orportion of the bushing may slip or slide relative to the wall or otherportion of the socket, while another end or portion of the bushingremains in nonslipping relation to the socket member. Thus, torsionalstress greater than can be absorbed by normal radial deformation ortwisting of the bushing is absorbed or resisted by longitudinal twistingor deformation thereof. This action of the pivotal connections disclosedherein is extremely beneficial, particularly in applications such as inthe automotive fleld.

The present invention is thus seen to provide a novel pivotal connectionconstruction embodying a resilient rubber cushion which has a portionthereof subjected solely to axial compression, while another portionthereof is subjected to circumferential distension and. axialelongation. Such an arrangement has been found to impart improvedoperating characteristics and has considerable resistance to wear.Additionally, pivotal connections constructed in accordance with thepresent invention may be quickly and easily assembled without special orexpensive tools, and may be manufactured in quantity at a relatively lowcost.

The principle of the present invention may be utilized in various ways,numerous modifications and alterations being contemplated, substitutionof parts and changes in construction being resorted to as desired, itbeingunderstood that the embodiments shown in the drawing and describedabove are given merely for purposes of explanation and illustrationwithout intending to limit the scope of the claims to the specificdetails disclosed.

What I claim is:

l. A pivotal connection between members having relative oscillatingmovement comprising a substantially cylindrical socket in one member, apintle assembly extending into said socket and having a cylindricalportion substantially concentric with the socket wall, and a resilientrubber bushing disposed about the pintle in the socket, said bushinghaving a body portion of substantially uniform diameter and thicknessfrom end to end within the socket and under circumferential tension andaxial elongation, a radially inwardly directed circumferential flangeintegral with the body portion seated against one end of the cylindricalportion of the pintle assembly and under circumferential tension, and anintegral flange on one end of the body portion remote from said inwardlydirected flange, said last named flange being substantially withoutcircumferential tension and under axial compression.

having a socket therein with a circular wall and .open at one end, apintle assembly extending axially through the socket, and a rubbercushion about the pintle in the socket, said cushion having a normaloutside diameter at the innermost end thereof disposed within the socketwhich is materially less than the diameter of the socket at that point,and at the outermost end thereof which is substantially equal to thediameter of the socket at that point, the pintle assembly being arrangedto distend the cushion into engagement with the socket wall throughoutsubstantially the entire length of the cushion, an integral radiallyextending flange on the outer end of the cushion, and an integralradially extending flange on the inner end of the cushion, said innerflange being circumferentially elongated upon distension of the cushion.

3. A pivotal connection construction comprising spaced metal members anda resilient tubular rubber bushing between the members, said bushinghaving a body portion, one end of which is substantially withoutcircumferential tension and the other end of which is undercircumferfrustoconical body havingtherein a frustoconical recess and acylindrical passage portion opening through, the small diameter end ofthe body, and a circumferential groove around the end of the body havingthe cylindrical passage for interlooking with one of the connectionmembers.

5. A pivotal connection comprising a member having a substantiallycylindrical socket open at opposite ends and a radial flange at one endof the socket, a pintle assembly extending 'axially through the socket,a rubber cushion about the pintle in the socket, said cushion having anormal outside diameter at one end less than the body portion of lessdiameter than the socket and an outwardly directed integral flange onone end 'engageablewith the external member to prevent the bushing beingdrawn completely into the socket, an internal member having one endreceivabl'e within the bushing and the external member and adapted tostretch the bushing into flange on thebushing engageable with the end ofthe internal member to prevent said end from corresponding diameter ofthe socket and at the other end substantially equal to the correspondingdiameter of the socket, the pintle assembly being arranged to distendthe cushion into engagement with the socket, and a groove around one endof the cushion to receive said radial flange and resist axial shiftingof the socke member on the cushion.

6. A rubber cushion for a pivotal connection comprising a sleeve-likebody having a radially directed flange on each end and a centrallydisposed, radial flange extending in a direction opposite to that of oneof the end flanges.

'7. A rubber cushion for a pivotal connection comprising a sleeve-likebody member having a passage therethrough to receive a pintle assembly,outwardly directed radial flanges on the ends of the body, and aninwardly directed radial flange in the central portion of the passage.

8. A pivotal connection for members having relative oscillating movementcomprising means providing a substantially circular socket on one of themembers, a pintle assembly on another of the members and disposed insaid socket, and a resilient and deformable annular bushing embracingthe pintle assembly within the socket,

. said bushing having a portion within the socket under circumferentialtension throughout its entire radial thickness and provided with anintegral radial flange, and an integral radial flange on the bushingunder axial compression and disposed outside of the socket.

9. A pivotal connection for members having relative oscillating movementcomprising means providing a substantially circular socket on one ofthemembers, a pintle assembly on another of the members and includingparts having different diameters disposed within the socket, and

a resilient and deformable annular bushing embracing the pintle assemblywithin the socket, said bushing having an integral radial flange undercircumferential tension and grippingly embracing a small diameter partof the pintle assembly, said flange being disposed against one end of alarge diameter part ofthe pintle assembly.

v10. In a pivotal connection, a resilient and deformable bushing whichin its unstressed form has a tubular frusto-conical portionwith integralradially extending flanges one at the large diameter end and one at thesmall diameter end of said tubular portion, and members forcooperatively engaging the bushing internally and externally to deformthe same so that said tubular portion becomes substantially cylindricaland of approximately equal diameter from end to end and said smalldiameter end flange is circumferentially tensioned.

11. In a pivotal connection, an external memher having a substantiallycylindrical socket projecting through the bushing.

12. In a pivotal connection, an external memher having a socket formedtherein, a resilient and deformable bushing receivable in the socket andcomprising a frusto-conicalbody having therein a frusto-conical recesssubstantially concentric to the outer surface of the body,- the wall ofsaid body being of progressively increasing thickness substantially fromthe large diameter end thereof substantially to the small diameter endthereof, and a radially directed circumferentially extending flange oneach end of the body, and an internal member receivable within saidrecess and formed to engage the body of the bushing throughoutsubstantially the entire length of the latter while the outside of thebushing body is circumferentially-engaged by the external memberthroughout substantially the entire length of said body.

13. In a pivotal connection, an external memher having a socket formedtherein, a resilient substantially its entire length while the outsideof the bushing body is circumferentially engaged by the external memberthroughout substantially the entire length of said body, one of saidflanges .being directed radially outvl'rardlyand disposed against an endof the external member and the other flange being directed radiallyinwardly and disposed against, an end of the inter- .nal member to holdthe bushing in predete'r mined axial position relative to said members.

14. A resilient and deformable tubularcushion for a pivotal connection,said cushion having a tapered body enclosinga tapered circular recessand with walls which increase in thickness progressively from the largeend to the small end of the body, and circumferentially extending" Iflanges formed on'the ends of the body and in-"' tegral therewith, theflange on the large diam-- eter end of the body being directed radiallyoutward only, to avoid restricting of the opening into the recess at thelarge diameter end of thebody.

15; A resilient and deformable cushion to be interposed between membersof a pivotal connection comprising a frusto-conical body having thereinafrusto-conical recess, a radially directed circumferentially extendingflange on each end of the body. each flange providing an annularabutment for one of the connection members, and a circumferential groovein the cushion for interlocking with onejof the connection members, onewall of said groove providing an annular abutment for one of theconnection mem bers and facing 'in the same direction as and axiallyoffset from the one of said first mentioned abutments which is at thesame end of the body. 16. A resilient and deformable cushion to beinterposed between members of a. pivotal conas and axially offset fromsaid first mentioned abutment.

17. A rubber cushion for a pivotal connection com-prising a tubular bodyof substantially circular cross section having an axial passagetherethrough to receive a pintle assembly, said body being tapered froma relatively small diameter central portion thereof to relatively largediameter end portions thereof, and an integral radially directed flangeon the body at the center thereof.

HOWARDM. DODGE.

